Liver Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland. Electronic address: firstname.lastname@example.org.
BACKGROUND & AIMS:
Liver biopsy is the standard for assessing hepatic fibrosis. Ultrasound transient elastography (TE) and the aspartate aminotransferase to platelet ratio index (APRI) are validated, non-invasive tests for identifying patients with cirrhosis. We evaluated discordance among TE, APRI, and histology diagnoses of cirrhosis.
We analyzed findings from 109 patients with chronic hepatitis C who underwent TE within 6 months of liver biopsy at the US National Institutes of Health from 2006 to 2011. Fibrosis was scored using the Ishak scale (0 to 6). APRI scores were calculated using data collected the day of the biopsy. Area under receiver operator characteristic curves for TE and APRI were calculated to distinguish patients with cirrhosis (Ishak scores of 5-6) from those without cirrhosis (Ishak scores of 0-4). The best cutoff and corresponding positive (PPV) and negative predictive values (NPV) were selected.
Based on biopsy analysis, 18% of the patients had no fibrosis, 52% had mild fibrosis, 17% had bridging fibrosis, and 13% had cirrhosis. A TE cutoff of 13.1 kPa identified patients with cirrhosis with the highest level of accuracy (100% sensitivity, 89% specificity, 58% PPV, 100% NPV), as did an APRI cutoff value of 1.0 (79% sensitivity, 78% specificity, 34% PPV, 96% NPV). Results from TE and APRI were discordant for 28% of cases. TE identified all cases of cirrhosis and an additional 10 patients who were not found to have cirrhosis based on histology analysis; 7 of these had clinical or radiological evidence of cirrhosis, indicating that the biopsy sample was not staged correctly.
TE increases the accuracies of biopsy and APRI analyses in identifying patients with cirrhosis. TE might also be used to screen patients for cirrhosis and identify those who should followed for development of hepatocellular carcinoma and varices.